This invention relates generally to crop harvesting and threshing machines, more commonly known as combines, and more particularly to the type of machine commonly referred to as an axial flow type combine wherein the crop material passes axially through an elongate casing and about each threshing and separating rotor contained therein. Specifically, the invention is concerned with material flow inhibiting means at the rear of the separating portion of the casing that decelerate and deflect the crop material to and through a discharge area. This invention is equally applicable to an axial flow type combine utilizing either a single threshing and separating rotor or double threshing and separating rotors.
The conventional type combines previously used pass the crop material to be threshed between a rotary cylinder and a stationary concave in a direction that was normal to the axis of the rotating cylinder and parallel with the longitudinal axis of the combine frame. In this system much of the grain contained in the crop material fed to the cylinder and the concave passes through the concave as threshed grain. The remainder of the material is conveyed to separating elements of the combine that traditionally include reciprocating or oscillating straw walkers, return pans, and chaffer sieves. Such conventional combines suffer from the major disadvantage of having a threshing capacity that is limited by the single pass of the crop material about the threshing cylinder. Combines of the axial flow type, in contrast, utilize single or dual threshing and separating rotors that permit the crop material to pass over the concave during the threshing process three or more times. This increased exposure to the rotors during the threshing process permits axial flow type combines to increase the amount of grain obtained from any crop passed therethrough when compared with conventional combines.
A feeder housing elevator on the front of the axial flow type combine delivers the cut crop material to the front or infeed end of the threshing and separating rotors. In one variation of the type of combine in which the instant invention can be utilized there are two rotors of generally cylindrical configuration which have a short infeed auger mounted to each of their forward ends. The rotors turn in opposite directions in parallel housings within a combined rotor casing and have separate threshing and separating portions. The threshing portion of each rotor or threshing cylinder has as many as four rasp bars fastened thereto in closely mounted pairs. Open type concaves are individually adjustable and sit beneath each rotor within the casing. The separating portion of the rotors have separator blades fixed to each of the two rotors to continue separating the grain from the crop material as the material moves rearwardly. The rearward movement of the crop material is aided by helical fins fixed to the upper portions of the rotor casing. At the rear of the rotors crop material is deflected into a transverse discharge beater and an auxilliary separating area which serve to remove the remaining grain and expel the crop material residue at the rear of the combine. These features are all shown in greater detail in prior U.S. Pat. Nos. 3,626,472, issued Dec. 7, 1971, and 3,742,686, issued July 3, 1973 both to Rowland-Hill.
When axial flow type combines are used in certain leguminous or grassy crops such as alfalfa, timothy or even clover there is a potential for the crop material to wrap about the rotating shafts and attached hubs or sleeves about which the threshing and separating rotors turn. Should the crop material continue to be transported rearwardly until it contacts the bulkhead at the extreme rear of the separating portion of the rotors crop material could become so tightly wrapped about the shafts and hubs of the rotors as to impair the operational characteristics of the overall machine. This operational impairment from wrapping potentially could cause eventual damage to the operating components of the rotors by breaking the seals to the rotor gear boxes, cause engine stallouts by binding the rotors so tightly that they cannot turn, or, at the least, prove to be extremely difficult to untwine or disentangle.
The foregoing problems are solved in the design of the machine comprising the present invention by decelerating the axial flow of crop material rearwardly about the threshing and separating rotors and by deflecting crop material into the discharge opening leading to the discharge beater paddle and beater case.